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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 631 records · Page 35Linked to original sources
PubMed1996

Different biodistribution of 99mTc-labelled chimeric mouse-human monoclonal antibody between athymic mice model and human.

Biodistribution of chimeric mouse/human monoclonal antibody against non-specific cross-reacting antigen (chNCA Ab) was studied in athymic mice and patients with metastatic bone disease. 99mTc-chNCA Ab showed a high labelling efficiency, stability and also a high binding ratio to human granulocytes. Since NCA showed cross-reactivity with carcinoembryonic antigen (CEA), animal experiments showed that 99mTc-chNCA Ab was accumulated in the xenografted tumour which expressed CEA, suggesting the preserved immunoreactivity of labelled materials. In the clinical study, injected 99mTc-chNCA Ab formed a high molecular weight complex immediately after intravenous administration and was trapped mainly in liver. The first-phase plasma half-life was 6.4 +/- 1.1 min. None of the patients showed adverse reaction or human antimurine or anti-chimeric antibody in their serum. 99mTc-chNCA Ab demonstrated remarkably different biodistribution between patients and the animal model and showed different pharmacokinetics from other murine and chimeric Abs reported previously. For safety HPLC analysis should be performed before clinical radioimmunodetection or radioimmunotherapy by incubating radiolabelled MAb with human serum under strict conditions.

Aged↗
PubMed1996

Constitutive expression of granulocyte-colony stimulating factor receptor on a human B-lymphoblastoid cell line.

The present study demonstrated that a human B-cell line derived from non-Hodgkin's lymphoma. HCF-MLpN. constitutively expressed G-CSF receptor on the cell surface. G-CSF binding to the cell surface was shown by immunofluorescence staining using biotinylated G-CSF preparation and analysed by flow cytometry. Specific binding of G-CSF to the cells was shown by pretreatment with unlabelled G-CSF. In the radioreceptor assay and Scatchard plot analysis using radiolabelled ligand, MLpN cells revealed a single species of binding site with an equilibrium dissociation constant of 167 (153-182) pM and a maximal binding site per cell of 1076 (1044-1116). The G-CSF receptor mRNA transcript was exhibited in the RNA from MLpN cells by reverse transcriptase polymerase chain reaction procedure. [3H]thymidine incorporation and trypan blue exclusion showed that the G-CSF receptor was capable of transducing the growth signal to HCF-MLpN cells. A small fraction of fresh B blasts from six patients with B-cell lymphoma and leukaemia displayed G-CSF binding by two-colour immunofluorescence staining. In contrast, a panel of seven B-cell lines was negative for the binding to biotinylated G-CSF preparation. These results suggest that the phenotype of G-CSF binding may be lost during the culture. The expression of G-CSF receptor in HCF-MLpN cells appeared to be exceptional.

B-Lymphocytes↗
PubMed1996

Circulating soluble intercellular adhesion molecule-1 (sICAM-1) in patients with sarcoidosis.

sICAM-1 has been elevated in sera of specific inflammatory diseases, and circulating sICAM-1 concentrations reflect disease activity in these diseases. We measured circulating sICAM-1 concentrations and serum angiotensin-converting enzyme (SACE) activity in patients with sarcoidosis. Patients with sarcoidosis had significantly increased circulating sICAM-1 concentrations (62.8 +/- 33.5 U/ml) and SACE activity (23.7 +/- 7.4 U/l) compared with controls (circulating sICAM-1 50.9 +/- 12.1 U/ml, and SACE 13.5 +/- 3.8 U/l). Successive measurements showed that circulating sICAM-1 values changed in parallel with disease activity in sarcoidosis. In the progressive disease group (progressed or without change for 2 years or more), circulating sICAM-1 values (102.2 +/- 35.3 U/ml) at the time of diagnosis were significantly increased compared with those in the regressive disease group (disappeared or regressed within 2 years) 46.4 +/- 12.6 U/ml). However, there was no significant difference in SACE activity of the regressive and progressive disease groups. Fifteen patients with a high value of circulating sICAM-1 (> 75 U/ml, mean of controls + 2 s.d.) all had progressive disease, while only 15 of 44 patients with a high value of SACE had progressive disease. Circulating sICAM-1 will be a useful blood marker to predict outcome and to monitor disease activity in sarcoidosis.

Adolescent↗
PubMed1996

Cell surface peptidases in human endometrium.

Three cell surface peptidases have been shown to be present in the human endometrium. Aminopeptidase N and neutral endopeptidase are detected on the endometrial stromal cells and decidual cells, while dipeptidyl peptidase IV is detected on the endometrial glandular cells and surface epithelium. As these cell surface peptidases can degrade a variety of biologically-active peptides including cytokines and growth factors, they are considered to be involved in the local metabolism of these molecules. In addition, recent studies have indicated that they are involved in local immune responses, cell attachment, and cellular maturation/ differentiation of endometrial cells, and suggest an important role of these endometrial cell surface peptidases in implantation processes.

Aminopeptidases↗
PubMed1996

Purification and refolding of recombinant human proMMP-7 (pro-matrilysin) expressed in Escherichia coli and its characterization.

Human matrix metalloproteinase-7 (MMP-7 = matrilysin) was overproduced in Escherichia coli as a recombinant zymogen (31 kDa), the C-terminus of which bears artificial hexa-histidines. Most of the enzyme was isolated from the insoluble fraction of the cell lysate and purified by a single step using Ni-NTA resin after solubilization of the precipitates with 8 M urea solution. The resin-bound recombinant protein was refolded into a form that is activatable by p-amino-phenylmercuric acetate in an autocatalytic manner. The activated enzyme cleaved a synthetic peptide substrate at the reported site for MMP-7. Digestion of carboxymethylated transferrin (a natural substrate of MMP-7) by the recombinant proteinase generated fragments with the same peptide map as in the case of native purified MMP-7. The autocatalytic activation and enzyme reaction were entirely dependent on the presence of calcium and zinc ions. The enzyme activity to cleave carboxymethylated transferrin was inhibited by tissue inhibitors of metalloproteinases-1 and -2, MMP-specific inhibitors. The activity of the recombinant MMP-7 was also inhibited by a synthetic peptide derived from a part of the cysteine switch that maintains the zymogen in an inactive state. Thus, we report here a simple means of preparing a large quantity of recombinant proMMP-7 that can be used to study the activation mechanism and to screen synthetic inhibitors.

Amino Acid Sequence↗
PubMed1996

Importance of N-terminal regions of G protein alpha subunits for the activation of phospholipase C in Xenopus oocytes.

The alpha subunits of Gq family G proteins, GL1 alpha and GL2 alpha, are bovine homologues of mouse G14 alpha and G11 alpha, respectively, and are closely related to each other. When expressed in Xenopus oocytes together with metabotropic glutamate receptors, GL2 alpha activates endogenous phospholipase C (PLCx) in response to glutamate stimulation, whereas GL1 alpha inhibits the activation of PLCx. By examining the properties of 10 chimeras between GL1 alpha and GL2 alpha and their mutants, we tried to identify the regions on the G alpha proteins that are important for the activation of PLCx. The results indicated that a necessary (but not sufficient) condition for a chimeric G alpha protein to be able to clearly activate PLCx was that its N-terminal quarter portion should be derived from GL2 alpha. No correlation was found between the origin (GL1 alpha or GL2 alpha) of C-terminal regions of the chimeras and the ability of chimeras to activate PLCx. One of the chimeras is different from GL2 alpha at only four amino acid residues in the N-terminal region, and yet it could not activate PLCx. When one of the four residues, Ser-59, in the chimera was mutated back to Ala as in the original GL2 alpha, the resulting mutant became capable of activating PLCx. This residue is localized in the midst of the N-terminal linker connecting the two major domains in the G alpha proteins. These results indicate that Ala-59 is critical for the activation of PLCx, and that the linker may play important roles in determining functions of G alpha proteins.

Animals↗
PubMed1996

Retropharyngeal abscess after radiation therapy and cis-platinum, 5-fluorouracil treatment for nasopharyngeal carcinoma with collagen disease: report of two patients and a review of the literature.

Collagen disease are frequently associated with malignant tumors. Recently, radiotherapy combined with chemotherapy has been recommended for improving the efficacy of treatment for nasopharyngeal carcinoma. Two patients with nasopharyngeal carcinoma complicated by collagen diseases (dermatomyositis in one, and Sjögren's syndrome with mixed connective tissue disease in the other) were given radiotherapy combined with chemotherapy consisting of cis-platinum and 5-fluorouracil. Following this combination therapy, both patients developed retropharyngeal abscess and ulceration of the mucosal membrane on the posterior wall of the oropharynx; there was no tumor cell involvement. Because these injuries were more severe than would have been expected from radiotherapy alone, it is recommended that special attention be paid to combination therapy in patients with nasopharyngeal carcinoma complicated by collagen disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

The amino acid sequences of two alpha chains of hemoglobins from Komodo dragon Varanus komodoensis and phylogenetic relationships of amniotes.

To elucidate phylogenetic relationships among amniotes and the evolution of alpha globins, hemoglobins were analyzed from the Komodo dragon (Komodo monitor lizard) Varanus komodoensis, the world's largest extant lizard, inhabiting Komodo Islands, Indonesia. Four unique globin chains (alpha A, alpha D, beta B, and beta C) were isolated in an equal molar ratio by high performance liquid chromatography from the hemolysate. The amino acid sequences of two alpha chains were determined. The alpha D chain has a glutamine at E7 as does an alpha chain of a snake, Liophis miliaris, but the alpha A chain has a histidine at E7 like the majority of hemoglobins. Phylogenetic analyses of 19 globins including two alpha chains of Komodo dragon and ones from representative amniotes showed the following results: (1) The a chains of squamates (snakes and lizards), which have a glutamine at E7, are clustered with the embryonic alpha globin family, which typically includes the alpha D chain from birds; (2) birds form a sister group with other reptiles but not with mammals; (3) the genes for embryonic and adult types of alpha globins were possibly produced by duplication of the ancestral alpha gene before ancestral amniotes diverged, indicating that each of the present amniotes might carry descendants of the two types of alpha globin genes; (4) squamates first split off from the ancestor of other reptiles and birds.

Amino Acid Sequence↗
PubMed1996

A human/mouse chimeric monoclonal antibody against intercellular adhesion molecule-1 for tumor radioimmunoimaging.

A mouse-human chimeric antibody for intercellular adhesion molecule-1 (ICAM-1) was established by using heavy chain loss mouse mutant hybridoma and human immunoglobulin expression vector. The HA58 hybridoma secreted anti-ICAM-1 monoclonal antibody (MoAb) (IgG1, kappa). The gene of the mouse variable region of heavy chain was amplified and cloned by the polymerase chain reaction technique directly from the HA58 hybridoma RNA. The variable region of heavy chain was joined with an expression vector which contains human gamma 1 constant gene. The expression vector was transfected into heavy chain loss mutant cells HA58-7, which produced only murine immunoglobulin light chains. The resultant chimeric MoAb HA58, chHA58, retained full-binding reactivity to ICAM-1 compared with murine HA58 parental antibody. The chimeric MoAb chHA58 showed little antibody dependent cell-mediated cytotoxic activity against cultured tumor cells. Biodistribution studies with 99mTc-labeled chHA58 in nude mice bearing human gastric carcinoma JRST cells demonstrated that the tumor-blood ratio was 1.55 at 18 h after injection, when the tumors were clearly visible in gamma scintigraphy. These data suggest that chHA58 may be of practical use for radioimmunoimaging of a wide variety of tumors.

Amino Acid Sequence↗
PubMed1996

Effect of MUC1 mucin, an anti-adhesion molecule, on tumor cell growth.

MUC1 mucin is expressed in a wide variety of tumors and is considered to function as an anti-adhesion molecule which inhibits cell-to-cell interactions. To reveal the biological significance of this activity in tumor cells, MUC1 cDNA was transfected into EJNIH3T3 cells and human colon cancer cell lines, CHCY1 and DLD1. The in vivo growth rate of MUC1+ (MUC1-transfected) EJNIH3T3, CHCY1 and DLD1 cells in SCID mice was clearly lower than that of MUC1- (mock transfectant) cells. Several in vitro experiments using MUC1+ EJNIH3T3 cells were performed to analyze the mechanisms for the decreased in vivo tumor growth. It was found that (i) the in vitro growth rate of MUC1+ EJNIH3T3 cells was also decreased compared to that of MUC1- cells, (ii)the DNA synthesis of MUC1+ EJNIH3T3 cells after stimulation with either growth factor (fetal calf serum or bombesin) or extracellular matrix (collagen or fibronectin) was lower than that of MUC1- cells, and (iii) MUC1+ EJNIH3T3 cells grew more slowly than MUC1- cells on both collagen- and fibronectin-coated dishes. These data suggest that MUC1 mucin may regulate tumor cell growth through inhibition of cell-to-cell, growth factor-to-receptor and cell-to-matrix interactions.

Acetylgalactosamine↗
PubMed1996

Soluble intercellular adhesion molecule-1 and soluble E-selectin levels in patients with atopic dermatitis.

The serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin (sE-selectin) were determined by double determinant immunoassay (DDIA), in 37 patients with atopic dermatitis (AD) and 31 age- and sex-matched healthy control subjects. Both sICAM-1 and sE-selectin levels were significantly higher in patients with AD than in healthy controls (P < 0.01), and were correlated with disease severity. A longitudinal study of patients with AD revealed that the levels of sICAM-1 decreased in those in whom symptoms improved. The sICAM-1 levels were significantly correlated with those of sE-selectin. Our studies suggest that such high levels of serum sICAM-1 and sE-selectin may affect the immune response in patients with AD. The levels of sICAM-1 and sE-selectin may be a useful immunological parameter for monitoring disease activity in AD.

Adolescent↗
PubMed1996

Double determinant immuno-polymerase chain reaction for detecting soluble intercellular adhesion molecule-1.

A sensitive method for the detection of antigens in sera, termed double determinant immuno-polymerase chain reaction (DDI-PCR), was developed using two monoclonal antibodies (MoAbs) in which the antigens are sandwiched and a specific DNA molecule as a marker. Instead of the antigen itself, the first MoAb to bind the circulating antigens was immobilized. After the biotinylated second MoAb was bound to the antigen, free streptavidin was used to attach a biotinylated DNA to the biotinylated second MoAb. The biotinylated DNA complexed with antigen-antibody-streptavidin was amplified by PCR. The PCR products were analyzed by Southern blot hybridization after agarose gel electrophoresis. Compared with the conventional ELISA using soluble intercellular adhesion molecule-1 (sICAM-1) in the supernatant of cultured Panc-1 cells as an antigen, our DDI-PCR was 10(3) times more sensitive in detection limit. In both the culture medium and sera from gastric cancer patients of high sICAM-1 titer, an approximately 10(3)-fold enhancement in detection sensitivity was obtained compared with ELISA. In addition, the DDI-PCR system can detect the antigen in sera at a level below the detection limit of traditional ELISA methods with high sensitivity. Thus, DDI-PCR has the significant advantage that it can be readily applied to any antigen-antibody system with two MoAbs without making any original molecules.

Animals↗
PubMed1996

Increase in shedding of intercellular adhesion molecule-1 in human malignant melanoma cell lines treated with hyperthermia in vitro.

Human malignant melanoma cell lines were found to increase shedding of soluble intercellular adhesion molecule-1 (sICAM-1) into the culture medium when the cells were treated with hyperthermia at 41-43 degrees C for 3-6 hr in vitro. The content of ICAM-1 in the cell lysate was also found to be increased after hyperthermia. The increased rate of ICAM-1 concentration in the cells was at maximum when they were incubated at 41 degrees C for 3 hr. Also, the melanoma cell lines heat-treated at 41 degrees C showed more intense immunofluorescence in the ICAM-1 expression on the cell surface. It remains to be investigated further whether the effects of hyperthermia on the ICAM-1 expression in melanoma cells is to augment membrane ICAM-1 expression, which in turn leads to shedding of soluble ICAM-1 or only to acceleration of shedding of sICAM-1 by unknown mechanisms.

Cytosol↗
PubMed1996

Detection of antiendometrial antibodies in patients with endometriosis by cell ELISA.

PROBLEM: To determine whether infertile patients with endometriosis have serum antiendometrial antibodies. METHODS: Sera from 40 infertile patients with or without endometriosis were tested by cell enzyme-linked immunosorbent assay (ELISA), in which endometrial cancer cells were used as endometrial antigens, and uterine cervix cancer cells as control antigens. As a negative control, eight healthy adult males were included. The level greater than the mean +/- 2 standard deviations (SD) of the male control group was judged positive. RESULTS: The mean value of antiendometrial antibody level was significantly higher in patients with endometriosis than in those without endometriosis (ANOVA, P < 0.01). The frequency of antiendometrial antibody-positive patients was also higher in the former than in the latter (chi 2 test, P < 0.05). However, when uterine cervix cancer cells were used as antigens, no difference was observed in the mean antibody levels or in the positive rates between the two groups. CONCLUSIONS: Endometriosis seems to be associated with autoantibody production against the endometrium-related antigen(s).

Adult↗
PubMed1996

Circulating intercellular adhesion molecule-1 and its cellular expression in head and neck non-Hodgkin's lymphomas, including lethal midline granuloma.

Extranodal non-Hodgkin's lymphoma in the head and neck, especially T-cell lymphoma of the lethal midline granuloma (LMG) type, has unique clinical and histologic features differentiating it from other lymphomas. The authors measured soluble intercellular adhesion molecule-1 (ICAM-1) in sera from 12 patients with T-cell lymphoma of the LMG type and from 52 patients with other head and neck non-Hodgkin's lymphomas, by double-determinant immunoassay. The expression of ICAM-1 in lymphoma tissue was examined in 26 patients by the avidin-biotin immunoperoxidase method. The serum ICAM-1 levels were significantly higher in T-cell lymphoma of the LMG type than in other head and neck lymphomas or in healthy adult controls. Elevated levels of serum ICAM-1 were associated with increased levels of serum lactate dehydrogenase, poor prognosis, and impaired T-cell-dependent immune functions, both in T-cell lymphoma of the LMG type and in other head and neck lymphomas. When we monitored serum ICAM-1 levels in individual patients, the level decreased in the complete remission interval compared to before treatment and went up again when the lymphoma relapsed. Although the staining intensities of ICAM-1 in lymphoma cells were not related to serum ICAM-1 levels, a markedly intense expression of ICAM-1 was found on the angiocentric or angiodestructive lymphoreticular infiltrate region in the tissues from T-cell lymphoma of the LMG type. A higher serum ICAM-1 level and its tissue expression in T-cell lymphoma of the LMG type may be one of the clues to understanding this particular lymphoma. The serum ICAM-1 level could be an efficient parameter for monitoring the clinical course of head and neck non-Hodgkin's lymphomas.

Adult↗
PubMed1996

Progesterone stimulates the induction of human endometrial CD56+ lymphocytes in an in vitro culture system.

An unusual population of large granular lymphocytes (LGL) with the surface phenotype CD56(bright+)/CD16-/CD3- increases in the human endometrium during the late secretory phase and early pregnancy. To identify the factor(s) that induces CD56+ LGL in the human endometrium, we isolated endometrial leukocytes from nonpregnant human endometrium and investigated changes in CD56+ cells during culture with various factors. Isolated endometrial leukocyte-rich fraction and peripheral blood mononuclear cells were cultured for 6 days in the presence of progesterone, estradiol, PRL, or hCG, then nonadherent cells were collected and examined immunocytochemically. Endometrial leukocyte-rich fractions were composed of leukocytes and endometrial stromal cells, and 53.2 +/- 5.8% of them expressed CD45 antigen before culture. Therefore, leukocytes and endometrial stromal cells were cocultured in these endometrial leukocyte-rich fraction cultures. The percentage of CD56+ cells in endometrial leukocyte-rich fractions cultured with progesterone was significantly higher than that in fractions without progesterone. On the other hand, estradiol, PRL, and hCG did not significantly induce CD56+ cells in endometrial leukocyte-rich fractions. There was no significant difference in the percentage of CD56+ cells between peripheral blood mononuclear cell cultures with and without progesterone. These findings suggest that progesterone is an important factor for the in situ proliferation or differentiation of CD56+ LGL in human endometrium.

Adult↗